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NASA SLS/Orion/Payloads

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52 minutes ago, KSK said:

.

5.  A genuine question here - booster explosions look extremely violent but how much force is that explosion actually generating?

 

 

Less than you’d think. Liquid fuel boosters (Shuttle ET included) don’t really explode except in the broadest sense of the word. It’s more of a rapid uncontrolled combustion or conflagration as the propellants mix. No shock wave is produced as that would require a detonation (supersonic explosion front). I triggered an explanation of it somewhere else in this sub forum; I’ll try to find it. 

A solid propellant factory in Utah once exploded; one could see the shockwave racing across the desert. 

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Posted (edited)
4 hours ago, KSK said:

I recall a SpaceX mission which ended pretty violently (CRS-7??) with a second stage RUD - which, from video footage, appeared to be survivable for the capsule parked on top.

Correct. The Dragon did survive until splashdown.

4 hours ago, KSK said:

I recall that the Orbiter survived the explosion more-or-less intact but broke up afterwards due to aerodynamic stresses.

I've heard it was destroyed after splashdown.

4 hours ago, KSK said:

5.  A genuine question here - booster explosions look extremely violent but how much force is that explosion actually generating?

I've heard numbers like 10mT nuclear blast if a fully fueled Saturn V exploded on the launchpad. I'm assuming that such a value is based on 100% of the fuel detonating (both cryogenics and hypergols). That said- I have no citation or basis on that value so take that with a Planck unit sized grain of salt.

Edited by ZooNamedGames

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18 hours ago, ZooNamedGames said:

I've heard numbers like 10mT nuclear blast if a fully fueled Saturn V exploded on the launchpad. I'm assuming that such a value is based on 100% of the fuel detonating (both cryogenics and hypergols). That said- I have no citation or basis on that value so take that with a Planck unit sized grain of salt.

The closest comparison we've got is the N-1 blowing up on the pad, which is estimated to have been the largest non-nuclear explosion of all time, yet only burnt about half the rocket's fuel.

LC 39 was designed to mitigate the destruction of a Saturn-class rocket as much as possible, mainly through distance (seriously, compare just how big the it is compared to anything else). Even so, the pad where it occurred would almost certainly be a goner, it's just everything else should be far enough away to come out (mostly) unscathed.

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1 hour ago, jadebenn said:

The closest comparison we've got is the N-1 blowing up on the pad, which is estimated to have been the largest non-nuclear explosion of all time, yet only burnt about half the rocket's fuel.

LC 39 was designed to mitigate the destruction of a Saturn-class rocket as much as possible, mainly through distance (seriously, compare just how big the it is compared to anything else). Even so, the pad where it occurred would almost certainly be a goner, it's just everything else should be far enough away to come out (mostly) unscathed.

The shockwave hitting the side of the VAB would likely damage the concrete(?) paneling on the outside. Requiring massive repair efforts even at said distance.

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There is no way it's mT.

Kilotons, maybe, not 10 megatons, no way.

Were the N1 incidents deflagrations, or actual explosions (or a combination with a subset as explosion, and the rest deflagration)?

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1 hour ago, ZooNamedGames said:

The shockwave hitting the side of the VAB would likely damage the concrete(?) paneling on the outside. Requiring massive repair efforts even at said distance.

No detonation = no shockwave. The fuel can only explode as fast as it contacts oxidizer. Although I am curious how big the fireball would be. About the same size as the N-1, I guess. 

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Posted (edited)
1 hour ago, ZooNamedGames said:

The shockwave hitting the side of the VAB would likely damage the concrete(?) paneling on the outside. Requiring massive repair efforts even at said distance.

The VAB does not use concrete panelling. I can't remember what material it is. I think it's either aluminum or fiberglass.

The panels are designed to blow out if there's a big pressure imbalance to avoid damage to the underlying structure. This mainly comes into play with inclement weather like hurricanes, but if there's a shockwave it should serve the same function.

40 minutes ago, tater said:

There is no way it's mT.

Kilotons, maybe, not 10 megatons, no way.

Were the N1 incidents deflagrations, or actual explosions (or a combination with a subset as explosion, and the rest deflagration)?

Yeah, not megatons. Wikipedia says the N-1 explosion was 6.93 kT, but it also says that 85% of the fuel in the N-1 wasn't consumed in it.

I believe LC-39 was designed with the worst case scenario in-mind: with 100% of the fuel in a Saturn V-class rocket being consumed in the conflagration.

Edited by jadebenn

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The F9 pad explosion was the worst at the Cape in a long, long time, and it was not an explosion, but a deflagration as I recall.

Getting Saturn to actually explode would be difficult, and if it did, I think only the one stage that you got to explode would explode, then the rest would be fire. So worst case would be to calculate for S1.

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An explosion can result from either a deflagration or a detonation. Explosion is a general term for an accelerated release of energy generating extreme temperatures, releasing of gases and expanding volume. A detonation involves an explosion wavefront that is supersonic. A deflagration wavefront is subsonic. But both are explosions.

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4 minutes ago, Brotoro said:

An explosion can result from either a deflagration or a detonation. Explosion is a general term for an accelerated release of energy generating extreme temperatures, releasing of gases and expanding volume. A detonation involves an explosion wavefront that is supersonic. A deflagration wavefront is subsonic. But both are explosions.

Yeah, but comparing something measured in tons (or kilotons, or megatons) of TNT is a de facto statement it's a detonation they are comparing to.

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1 hour ago, tater said:

Yeah, but comparing something measured in tons (or kilotons, or megatons) of TNT is a de facto statement it's a detonation they are comparing to.

A lot of times when I see this, they are just comparing the total energy release of the explosion (which may be from either a detonation or deflagration) to the equivalent energy release of a mass of TNT (which is a detonation). So although the energy releases of those explosions may be equivalent, the effects of the explosions will be different.

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15 minutes ago, Brotoro said:

A lot of times when I see this, they are just comparing the total energy release of the explosion (which may be from either a detonation or deflagration) to the equivalent energy release of a mass of TNT (which is a detonation). So although the energy releases of those explosions may be equivalent, the effects of the explosions will be different.

Yeah, I'd not use kilotons for something that doesn't act like a high explosive.

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Posted (edited)

Saturn-V:
Stage I: 2300 t, kerolox, ratio 2.37
Stage II+III: 500+130 t, hydrolox, ratio 16
kerosene : mass = 2300 * 0.95 / (2.37 + 1) * 1 ~= 650 t, 40 MJ/kg
hydrogen : mass = 630 * 0.95 / (16 + 1) * 1 ~= 35 t, 214 MJ/kg
TNT ~= 650 * 40 /4.2 + 35*214/4.2 ~= 8 000 t

N-1:
Mass = 2700..2900 t, kerolox, ratio 2.37
kerosene: mass = 2900 * 0.95 / (2.37+1) * 1 ~= 820 t, 40 MJ/kg
TNT ~= 820 * 40 /4.2 ~= 7 800 t

I.e. both contain ~ 8 000 t of TNT in total.
But as it is not uniformly mixed in the oxidizer, only small part of it detonates.
So, if "85% didn't detonate", then the explosion yield ~0.15 * 8 = 1.2 kt.

Windows (tm) and doors will be destroyed in radius ~15 km * (1.2/1000)1/3 ~= 1.5 km.

Edited by kerbiloid

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5 hours ago, kerbiloid said:

Saturn-V:
Stage I: 2300 t, kerolox, ratio 2.37
Stage II+III: 500+130 t, hydrolox, ratio 16
kerosene : mass = 2300 * 0.95 / (2.37 + 1) * 1 ~= 650 t, 40 MJ/kg
hydrogen : mass = 630 * 0.95 / (16 + 1) * 1 ~= 35 t, 214 MJ/kg
TNT ~= 650 * 40 /4.2 + 35*214/4.2 ~= 8 000 t

N-1:
Mass = 2700..2900 t, kerolox, ratio 2.37
kerosene: mass = 2900 * 0.95 / (2.37+1) * 1 ~= 820 t, 40 MJ/kg
TNT ~= 820 * 40 /4.2 ~= 7 800 t

I.e. both contain ~ 8 000 t of TNT in total.
But as it is not uniformly mixed in the oxidizer, only small part of it detonates.
So, if "85% didn't detonate", then the explosion yield ~0.15 * 8 = 1.2 kt.

Windows (tm) and doors will be destroyed in radius ~15 km * (1.2/1000)1/3 ~= 1.5 km.

To return to the topic at hand- how much would that be if a SLS detonated?

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Mock up of toilet for Orion. You'd think this would be flight article by now, honestly:

 

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10 hours ago, tater said:

Mock up of toilet for Orion. You'd think this would be flight article by now, honestly:

 

Do they really need a flight Article for an unmanned flight?

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31 minutes ago, ZooNamedGames said:

Do they really need a flight Article for an unmanned flight?

Yeah. The entire vehicle should be flight article.

The crew is not spending 2 weeks in flight without a toilet. They should test it, you don;t want to find the critical valve fails in a launch vibration regime that wasn't (or could not be) tested.

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1 minute ago, tater said:

Yeah. The entire vehicle should be flight article.

The crew is not spending 2 weeks in flight without a toilet. They should test it, you don;t want to find the critical valve fails in a launch vibration regime that wasn't (or could not be) tested.

Tbf, I doubt they will be using such a device even on A-2. Likely going to just use something more proven from the ISS or Soyuz. Whatever gets the job done with a known history in the space provided (which, is actually quite massive comparatively to other space capsules).

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1 minute ago, ZooNamedGames said:

Tbf, I doubt they will be using such a device even on A-2. Likely going to just use something more proven from the ISS or Soyuz. Whatever gets the job done with a known history in the space provided (which, is actually quite massive comparatively to other space capsules).

There is zero excuse that a vehicle that has been worked on for so long, and at such cost is not entirely capable on the first launch.

Sorry, it's pathetic. This stuff should be the short pole, it should literally have been waiting for installation as flight article years ago.

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Posted (edited)
4 minutes ago, tater said:

There is zero excuse that a vehicle that has been worked on for so long, and at such cost is not entirely capable on the first launch.

Sorry, it's pathetic. This stuff should be the short pole, it should literally have been waiting for installation as flight article years ago.

I recall some people being up in arms about NASA testing launch vehicles/spacecraft for the first time with crew (cough Space Shuttle cough). Now people are up in arms because A-1 ain't manned. I mean at least this isn't AS-201 where it only goes into LEO. It at least it's going somewhere. Plus carrying payload.

That said, the biggest roadblock is likely from ESA and not getting the SM ready in time.

Edited by ZooNamedGames

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Posted (edited)

It kinda feels like in the absence of competition up until the recent commercial space boom, the ULA have been just milking money out of the government... and now it feels like they are having to actually come up with the goods, and what do we get? a hastily 3d printed mock up? >.> where did the money go?

Edited by Dale Christopher

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